At Madaster, we believe enabling a circular economy is critical to tackling climate change, yet across the industry, carbon remains the key focus area. For this year’s London Climate Action Week our Madaster Network event explored this dynamic further, unpacking the relationship between circular and low carbon ambitions in the built environment sector.
We brought together speakers with a range of experience and perspectives across policy, product delivery, development and research. The dialogue explored what the data is showing us, whether material impacts can be included into net zero pathways and to what extent there is a need to choose between the two outcomes.
It became clear that there are both synergies and conflicts. Two main themes emerged – the first, recognising the time-value of carbon – when in the life cycle will carbon be emitted or saved; the second, the importance of sustainability beyond carbon – a need for multiple metrics to understand the full picture.
The time value of carbon
“There is a trade-off aspect to consider when it comes to emissions, it’s all about timing”
The big question is should we be relentlessly focused on reducing embodied carbon today, or can we take a more fluid approach, exceeding our immediate carbon budgets to achieve lower operational emission in the future? Different carbon and circular economy strategies apply in different building typologies, phases of development and use cases. They can produce very different outcomes for design, material choices, demolition, reuse and energy systems.
“Some circular economy approaches in the built environment build in impact reductions for future life cycles”
A lot of circular economy strategies deliver benefits to the second life of a building or product. We need to build for durability, adaptability and reusability to make sure that in the future we are not in the same position that we are now, where materials can be very hard to reuse. This can require additional carbon and material resource investment up front, which is an issue when we need to urgently reduce our emissions in the short-term. We must carefully consider this temporal question of where we are putting our resources, our energy and our attention.
“By exploring the idea of an ‘adaptability carbon cost’ it is possible to look for sweet spots in design and engineering”
Where lean design (reduction in use of materials, for example) can reduce upfront embodied carbon, design for adaptability can achieve greater embodied carbon reductions in the long-term, as it can allow for greater flexibility in future use. This is a particularly delicate balancing act from a structural engineering perspective; load carrying capacity and vibration limits are key considerations.
Sustainability beyond carbon
“Carbon and circularity do go hand in hand, generally if you target circularity, you bring down your carbon footprint”
But it doesn’t always work the other way around. There are many more metrics to consider for circularity than for carbon measurement. This enables you to have a much broader picture to include material origin, toxicity, ‘demountability’ and ‘separability’, which will play a critical role in future emissions alongside operational building emissions and the embodied carbon footprint.
“We can’t ‘efficiency’ our way out of something caused by consumption”
Resource depletion should be a key consideration for the built environment. When extracting or manufacturing new material, even if the manufacturing has become carbon free, a blinkered focus on carbon will mean we ignore other critical planetary boundaries like land use, biodiversity, pollution and material resources.
“Circular economy is often thought of as the flipside of the coin, the ‘overlooked’ emissions”
There are several new policies emerging in London that encourage sustainability considerations beyond operational carbon. Circular Economy Statements that set out how the London Plan circular economy policy will be met are now required for all major referable planning applications. The City of London Carbon Options Guidance Planning Advice Notice pioneers a new optioneering exercise for planning proposals to compare development types from refurbishment to complete redevelopment, and the Net Zero Residential Retrofit Policy encourages investigation of retrofit and extension options before considering demolition.
Key take aways
The market is currently still carbon driven, but understanding of the role of circularity is improving, and the legislation is starting to catch up. We must pay more attention to the critical nature of considering when and how in the life cycle we set our carbon emissions targets. Circularity generally drives carbon reduction, but carbon cannot be used as a single metric for circularity.
Madaster is a data platform that creates a digital record of the materials and products in your building and allows you to unlock a wide range of financial and environmental insights which include whole life carbon and a range of other circularity metrics.
Many thanks to the members of the Madaster Network that contributed to these insights.